With the increase in the number of battery powered, portable devices used both commercially and for recreation, there is an increasing need to provide a long lasting, adaptable, efficient electrical source. Two-way radios, GPS equipment, portable computers, cell phones, CD and tape players and the like generally use conventional batteries as a power source. These batteries may be disposable or rechargeable. Regardless of the type of battery used, after a certain time, the batteries in the equipment must be replaced with new or recharged batteries. This is inconvenient and, in many situations, requires the user to carry spare batteries.
There have been a number of attempts to provide electrical generator units which derive their power from the walking movement of the user. For example, U.S. Pat. No. 4,674,199 to Lakic discloses a shoe with an internal warming mechanism. The warming mechanism comprises an electrical resistance coil in the sole or the covering of the shoe and a mechanical electricity generation mechanism in the heel of the shoe. The generator is driven by the up and down movement of a wearers' heel. The generator described by Lakic includes an armature mounted for rotational movement in a magnetic field and mechanically connected to a vertical post which depends from the under surface of the heel portion of the inner sole of the shoe.
U.S. Pat. No. 4,870,700 to Ormanns discloses a personal safety radio device which can be mounted in the heel of a work shoe. The radio includes a transmitter powered by a rechargeable accumulator, a receiver and an antenna arrangement. Ormanns teaches that the rechargeable accumulator may be charged by a generator arrangement which includes a piezo-electric converter. The piezo-electric converter is arranged in the shoe such that it is acted on by the weight of the person wearing the shoe and thus converts the pressure of the weight into electrical energy.
U.S. Pat. No. 5,167,082 to Chen discloses a dynamo-electric shoe which has a pressure-operated electric generator inside a water tight compartment adjacent to the heel portion of the shoe. An electrical socket is mounted on the sole of the shoe and a rechargeable battery cell is wired to the electrical socket. Chen teaches that the dynamo-electric shoe can be used to operate a portable wireless telephone, a portable radio, a light device, a heating device or the like. The generator disclosed by Chen is mechanical.
U.S. Pat. No. 5,495,682 also to Chen discloses a similar dynamo-electric shoe in which the mechanical electric generator is operated by pressure on a pivot plate mounted to the heel of the shoe.
Other mechanical-type electricity generators are disclosed in U.S. Pat. Nos. 4,782,608, 4,845,338 and 5,367,788.
Mechanical electricity generators of the type known in the art have a number of disadvantages in that they are generally heavy, expensive to construct, require specialist shoe design, and are prone to mechanical breakdown.
It is an object of the present invention to provide a footwear-based electrical generation system which overcomes at least one of the disadvantages of the prior art.